toxin levels that cause illness usually require S. aureus populations above about 105 CFU/g in the food
this toxin general causes a sudden onset of vomiting within a few hours of consuming the food and this vomiting generally lasts 4-5 hours - diarrhoea is not a feature.
at typical fridge temperatures (≤ 4 °C), S. aureus growth is effectively halted or becomes extremely slow, and enterotoxin production does not occur at these temperatures, nevertheless most would recommend sliced meats such as ham is consumed within 3-5 days when kept in a fridge and there has not been a “abuse period”
risk of enterotoxin food poisoning increases sharply if slices sit at room temperature (or warmer, e.g. buffet, car, esky at ambient) for several hours, especially if there is hand contact from a colonised handler, then are returned to the fridge; that abuse period is when toxin is formed and, once formed, the toxin is not destroyed by reheating or by refrigeration.
outbreaks are mostly linked to preparation and holding at unsafe temperatures in restaurants, delis or homes (food left in the danger zone), rather than to correctly refrigerated leftovers